Measuring Tidal Marsh Responses to Sea Level Rise

Funding:

NH Charitable Foundation Thomas Haas Fund / NH Coastal Program

Description:

Tidal marshes developed in New England during the past 4,000 years when sea levels rose slowly.  As marshes flood, grasses trap inorganic sediments and also infuse the soils with organic matter (roots and rhizomes).  Flooding by salt water is key to provide suspended sediments to the marsh surface and prevent the organic matter in the peat sediments from decomposing.  Local sea level rise has increased from 1 to 3 mm over the past two decades, and as tidal marshes flood more, scientists expect they will grow faster (up to a point).  Our project will deploy surface elevation tables (SETs) and measure surface accretion and elevation change at six stations in the Hampton Seabrook Estuary.  Change in sediment elevation is tracked by setting up the SET on a known benchmark and measuring the distance to the soil surface (Fig. 1). 

Surface accretion is measured as the depth of sediment covering a thin layer of white feldspar (inset).  Since tidal marshes have this amazing ability to grow in elevation as sea levels rise, they can help coastal communities track and adapt to rising sea levels.

Student Peter Wilkinson holding SET device just before attaching for measurements.  Inset shows a slice of marsh with sediment accreted over the white marker horizon.

Student Involvement:

Peter Wilkinson (UG); Steve Gaughan (MS)

Links:

http://des.nh.gov/organization/divisions/water/wmb/coastal/resilient-coast.htm

http://www.seacoastonline.com/article/20140617/NEWS/406170368

 

Contacts

David Burdick

603.862.5129
  • Interim Director of the Jackson Estuarine Laboratory
  • Research Associate Professor of Coastal Ecology and Restoration

Department of Natural Resources & the Environment
Jackson Estuarine Laboratory
85 Adams Point Road
Durham, NH 03824